A compound having a polymerizable group (polymerizable compound) is used for various optical materials. For example, after a polymerizable composition containing a polymerizable compound is aligned in a liquid-crystal state, it can be polymerized to produce a polymer having a uniform alignment. Such a polymer can be used for polarizers, retarders and the like necessary for displays. In many cases, for satisfying required optical properties, polymerization speed, solubility, melting point, glass transition temperature, polymer transparency, mechanical strength, surface hardness, heat resistance and lightproofness, a polymerizable composition containing two or more kinds of polymerizable compounds is used. In such a case, the polymerizable compounds to be used are desired to impart good physical properties to the polymerizable composition without having any negative influence on the other properties.
For improving the viewing angle of a liquid crystal display, it is desired to reduce the wavelength dispersion characteristic of birefringence of a retardation film, or to reverse it. As a material for the purpose, various polymerizable liquid crystal compounds having a reversed wavelength dispersion characteristic or a low wavelength dispersion characteristic have been developed. However, such a polymerizable compound causes crystal precipitation when added to a polymerizable composition and the storage stability thereof is insufficient (PTL 2 and PTL 3). On the other hand, in the case where a polymerizable composition is applied onto a substrate and polymerized thereon and the resultant filmy polymer is irradiated with UV light, there occur a problem that the filmy polymer often discolors or peels off from the substrate (PTL 1 to PTL 3). When the discolored or peeled film is used, for example, in a display, the brightness of the picture plane may be uneven, or the color may be unnatural, or intended optical characteristics could not be obtained, and there occurs a problem that the quality of display products is significantly lowered. Consequently, development of a polymerizable liquid crystal compound having a reversed wavelength dispersion property or a low wavelength dispersion property capable of solving the problems is desired.